Add metal_util component

As part of the investigation of the hangs in the Metal shader compiler,
we will be running some Metal code in the browser process. Create a
stand-alone component for Metal utility functions that will be used
in the browser process and also in the gpu process.

For the moment this functionality includes the C++ Metal types and
the function to select the default Metal device (low-power if
available). Functionality to compile a test shader to determine if
it hangs will also be moved there (and called from the browser
process).

Bug: 974219
Change-Id: Ic6a696686e0c438ec339c6cc40b8200be6b0a689
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1869127
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Eric Karl <ericrk@chromium.org>
Reviewed-by: Cait Phillips <caitkp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708798}

components/metal_util/BUILD.gn

+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//testing/test.gni")
+
+component("metal_util") {
+  output_name = "metal"
+
+  defines = [ "METAL_UTIL_IMPLEMENTATION" ]
+
+  sources = [
+    "device.h",
+    "device.mm",
+    "metal_util_export.h",
+    "types.h",
+  ]
+
+  deps = [
+    "//base",
+  ]
+
+  libs = [ "Metal.framework" ]
+}

components/metal_util/DEPS

+include_rules = [
+]

components/metal_util/OWNERS

+ccameron@chromium.org
+jvanverth@google.org
+
+# TEAM: graphics-dev@chromium.org
+# COMPONENT: Internals>Compositing

components/metal_util/README.md

+# //components/metal_util
+
+metal_util is a set of utility functions for the macOS Metal graphics library.
+This is to be a largely stand-alone library with minimal dependencies.

components/metal_util/device.h

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_METAL_UTIL_DEVICE_H_
+#define COMPONENTS_METAL_UTIL_DEVICE_H_
+
+#include "components/metal_util/metal_util_export.h"
+#include "components/metal_util/types.h"
+
+namespace metal {
+
+// Return a low-power device, if one exists, otherwise return the system default
+// device.
+MTLDevicePtr METAL_UTIL_EXPORT CreateDefaultDevice();
+
+}  // namespace metal
+
+#endif  // COMPONENTS_METAL_UTIL_DEVICE_H_

components/metal_util/device.mm

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/metal_util/device.h"
+
+#import <Metal/Metal.h>
+
+#include "base/mac/scoped_nsobject.h"
+
+namespace metal {
+
+MTLDevicePtr CreateDefaultDevice() {
+  if (@available(macOS 10.11, *)) {
+    // First attempt to find a low power device to use.
+    base::scoped_nsprotocol<id<MTLDevice>> device_to_use;
+    base::scoped_nsobject<NSArray<id<MTLDevice>>> devices(MTLCopyAllDevices());
+    for (id<MTLDevice> device in devices.get()) {
+      if ([device isLowPower]) {
+        device_to_use.reset(device, base::scoped_policy::RETAIN);
+        break;
+      }
+    }
+    // Failing that, use the system default device.
+    if (!device_to_use)
+      device_to_use.reset(MTLCreateSystemDefaultDevice());
+    if (!device_to_use) {
+      DLOG(ERROR) << "Failed to find MTLDevice.";
+      return nullptr;
+    }
+    return device_to_use.release();
+  }
+  // If no device was found, or if the macOS version is too old for Metal,
+  // return no context provider.
+  return nullptr;
+}
+
+}  // namespace metal

components/metal_util/metal_util_export.h

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_METAL_UTIL_METAL_UTIL_EXPORT_H_
+#define COMPONENTS_METAL_UTIL_METAL_UTIL_EXPORT_H_
+
+#if defined(COMPONENT_BUILD)
+#if defined(WIN32)
+
+#if defined(METAL_UTIL_IMPLEMENTATION)
+#define METAL_UTIL_EXPORT __declspec(dllexport)
+#else
+#define METAL_UTIL_EXPORT __declspec(dllimport)
+#endif  // defined(METAL_UTIL_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+#if defined(METAL_UTIL_IMPLEMENTATION)
+#define METAL_UTIL_EXPORT __attribute__((visibility("default")))
+#else
+#define METAL_UTIL_EXPORT
+#endif
+#endif
+
+#else  // defined(COMPONENT_BUILD)
+#define METAL_UTIL_EXPORT
+#endif
+
+#endif  // COMPONENTS_METAL_UTIL_METAL_UTIL_EXPORT_H_

components/metal_util/types.h

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_METAL_UTIL_TYPES_H_
+#define COMPONENTS_METAL_UTIL_TYPES_H_
+
+#if __OBJC__
+@protocol MTLDevice;
+#endif
+
+namespace metal {
+
+// Metal's API uses Objective-C types, which cannot be included in C++ sources.
+// This file defines types that resolve to Metal types in Objective-C sources
+// and can be included in C++ sources.
+#if __OBJC__
+using MTLDevicePtr = id<MTLDevice>;
+#else
+class MTLDeviceProtocol;
+using MTLDevicePtr = MTLDeviceProtocol*;
+#endif
+
+}  // namespace metal
+
+#endif  // COMPONENTS_METAL_UTIL_TYPES_H_

components/viz/common/BUILD.gn

@@ -61,6 +61,7 @@ if (is_mac) {
     deps = [
       "//base",
       "//components/crash/core/common:crash_key",
+      "//components/metal_util",
       "//ui/gfx",
       "//ui/gl",
     ]

components/viz/common/gpu/DEPS

@@ -3,6 +3,7 @@
 include_rules = [
   "+cc/output",
   "+cc/resources",
+  "+components/metal_util",
   "+gpu/command_buffer",
   "+gpu/GLES2/gl2extchromium.h",
   "+gpu/vulkan",

components/viz/common/gpu/metal_context_provider.h

@@ -6,18 +6,11 @@
 #define COMPONENTS_VIZ_COMMON_GPU_METAL_CONTEXT_PROVIDER_H_
 
 #include <memory>
+#include "components/metal_util/types.h"
 #include "components/viz/common/viz_metal_context_provider_export.h"
 
 class GrContext;
 
-#if __OBJC__
-@protocol MTLDevice;
-using MTLDevicePtr = id<MTLDevice>;
-#else
-class MTLDeviceProtocol;
-using MTLDevicePtr = MTLDeviceProtocol*;
-#endif
-
 namespace gl {
 class ProgressReporter;
 }  // namespace gl
@@ -33,7 +26,7 @@ class VIZ_METAL_CONTEXT_PROVIDER_EXPORT MetalContextProvider {
   virtual ~MetalContextProvider() {}
 
   virtual GrContext* GetGrContext() = 0;
-  virtual MTLDevicePtr GetMTLDevice() = 0;
+  virtual metal::MTLDevicePtr GetMTLDevice() = 0;
 
   // Set the progress reported used to prevent watchdog timeouts during longer
   // sequences of Metal API calls. It is guaranteed that no further calls to

components/viz/common/gpu/metal_context_provider.mm

@@ -9,6 +9,7 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/time/time.h"
+#include "components/metal_util/device.h"
 #include "components/viz/common/gpu/metal_api_proxy.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 
@@ -100,7 +101,7 @@ struct API_AVAILABLE(macos(10.11)) MetalContextProviderImpl
     [device_ setProgressReporter:progress_reporter];
   }
   GrContext* GetGrContext() override { return gr_context_.get(); }
-  MTLDevicePtr GetMTLDevice() override { return device_.get(); }
+  metal::MTLDevicePtr GetMTLDevice() override { return device_.get(); }
 
  private:
   base::scoped_nsobject<MTLDeviceProxy> device_;
@@ -116,17 +117,8 @@ struct API_AVAILABLE(macos(10.11)) MetalContextProviderImpl
 std::unique_ptr<MetalContextProvider> MetalContextProvider::Create() {
   if (@available(macOS 10.11, *)) {
     // First attempt to find a low power device to use.
-    base::scoped_nsprotocol<id<MTLDevice>> device_to_use;
-    base::scoped_nsobject<NSArray<id<MTLDevice>>> devices(MTLCopyAllDevices());
-    for (id<MTLDevice> device in devices.get()) {
-      if ([device isLowPower]) {
-        device_to_use.reset(device, base::scoped_policy::RETAIN);
-        break;
-      }
-    }
-    // Failing that, use the system default device.
-    if (!device_to_use)
-      device_to_use.reset(MTLCreateSystemDefaultDevice());
+    base::scoped_nsprotocol<id<MTLDevice>> device_to_use(
+        metal::CreateDefaultDevice());
     if (!device_to_use) {
       DLOG(ERROR) << "Failed to find MTLDevice.";
       return nullptr;